docs: Add slides for Pixi Build and conda-forge

content/other-tools/02_pixi_build.md

@@ -1,5 +1,7 @@
 # Pixi-build
 
+{button}`Slides <https://scikit-build.org/SIMPLE-Py/slides/5_02_pixi_build>`
+
 In this section we'll see how we can use [Pixi Build](https://pixi.prefix.dev/latest/build/getting_started/) to extend all of the packaging concepts that we've learned about so far into conda packages with as little additional effort as possible.
 Pixi Build allows for defining metadata in the Pixi manifest that define [package](https://pixi.prefix.dev/latest/reference/pixi_manifest/#the-package-section), [build](https://pixi.prefix.dev/latest/reference/pixi_manifest/#build-table), [build-dependencies](https://pixi.prefix.dev/latest/reference/pixi_manifest/#build-dependencies), [host-dependencies](https://pixi.prefix.dev/latest/reference/pixi_manifest/#host-dependencies), and [run-dependencies](https://pixi.prefix.dev/latest/reference/pixi_manifest/#host-dependencies) TOML tables.
 These tables can be used together with the information in the rest of the Pixi manifest to build and install conda packages without having to have the full formal specification of a `rattler-build` recipe, like those shown in the [Shipping to conda-forge section](https://scikit-build.org/SIMPLE-Py/conda-forge/).

slides/5_02_pixi_build.md

@@ -0,0 +1,340 @@
+---
+marp: true
+theme: simplepy
+paginate: true
+_paginate: skip
+_class: lead
+---
+
+# SIMPLE-Py
+
+## Pixi Build
+
+---
+
+# What is Pixi Build?
+
+- Extends everything we've learned so far to **conda packages** with as
+  little additional effort as possible
+- Package metadata lives directly in the Pixi manifest as TOML tables:
+  `package`, `build`, `build-dependencies`, `host-dependencies`, and
+  `run-dependencies`
+- Combined with the rest of the manifest, that's enough to build and
+  install conda packages — no full `rattler-build` recipe required
+- We'll adapt the examples from the previous packaging sections
+
+---
+
+# Basic packaging: starting point
+
+Take the `rescale` package from _Making a basic package_ and create a
+Pixi manifest as a `pyproject.toml` `[tool.pixi]` table:
+
+```bash
+pixi init --format pyproject
+```
+
+Environments are created automatically from the optional dependencies
+and dependency groups:
+
+```text
+✔ Added package 'rescale' as an editable dependency.
+✔ Added environment 'dev' from optional dependencies or dependency groups.
+```
+
+---
+
+# Enable Pixi Build
+
+Pixi Build is a **preview** feature — opt in:
+
+```toml
+preview = ["pixi-build"]
+```
+
+Add the platforms you might want to support (like normal):
+
+```bash
+pixi workspace platform add linux-64 osx-64 win-64 osx-arm64 linux-aarch64
+```
+
+Change `rescale` from a Python package dependency to a **conda package**
+dependency:
+
+```diff
+-[tool.pixi.pypi-dependencies]
+-rescale = { path = ".", editable = true }
++[tool.pixi.dependencies]
++rescale = { path = "." }
+```
+
+---
+
+# Define the conda package
+
+<div class="columns">
+<div>
+
+The `[package]` table and the Python build backend:
+
+```toml
+[tool.pixi.package]
+name = "rescale"
+version = "0.1.0"
+
+[tool.pixi.package.build.backend]
+name = "pixi-build-python"
+version = "0.*"
+```
+
+</div>
+<div>
+
+The `host` and `run` dependencies:
+
+```toml
+[tool.pixi.package.host-dependencies]
+hatchling = "*"
+
+[tool.pixi.package.run-dependencies]
+numpy = ">=1.24"
+```
+
+And a `tests` task for the `dev` feature:
+
+```bash
+pixi task add --feature dev tests "pytest tests"
+```
+
+</div>
+</div>
+
+---
+
+# The final `[tool.pixi]` manifest
+
+One `pyproject.toml` describes both the Python **and** conda package:
+
+<div class="columns">
+<div>
+
+```toml
+[tool.pixi.workspace]
+channels = ["conda-forge"]
+platforms = [
+  "linux-64", "osx-64", "win-64",
+  "osx-arm64", "linux-aarch64",
+]
+preview = ["pixi-build"]
+
+[tool.pixi.dependencies]
+rescale = { path = "." }
+
+[tool.pixi.package]
+name = "rescale"
+version = "0.1.0"
+```
+
+</div>
+<div>
+
+```toml
+[tool.pixi.package.build.backend]
+name = "pixi-build-python"
+version = "0.*"
+
+[tool.pixi.package.host-dependencies]
+hatchling = "*"
+
+[tool.pixi.package.run-dependencies]
+numpy = ">=1.24"
+
+[tool.pixi.feature.dev.tasks.tests]
+cmd = "pytest tests"
+```
+
+</div>
+</div>
+
+---
+
+# Building (and installing) the package
+
+Any Pixi command that needs an installed environment builds and
+installs the conda package (`pixi install`, `pixi run`, `pixi shell`):
+
+```bash
+pixi run tests
+```
+
+```console
+$ pixi list -x
+Installed for: linux-64
+Name     Version  Build                    Size  Kind   Source
+numpy    2.5.1    py314h2b28147_0      8.67 MiB  conda  https://conda.anaconda.org/conda-forge
+python   3.14.6   habeac84_100_cp314  35.02 MiB  conda  https://conda.anaconda.org/conda-forge
+rescale                                          conda  .
+```
+
+---
+
+# Building a conda package artifact
+
+[`pixi publish`](https://pixi.prefix.dev/latest/reference/cli/pixi/publish/)
+builds the conda package and publishes it to a conda channel
+(`--target-channel`) or a local directory (`--target-dir`):
+
+```text
+pixi publish --clean --target-dir .
+```
+
+```text
+📦 Publishing 1 package(s) to directory </path/to/cwd>
+✔ Successfully published 1 package(s) to directory </path/to/cwd>
+  - rescale-0.1.0-pyh4616a5c_0.conda
+```
+
+Inspect the package with `rattler-build`:
+
+```text
+pixi global install rattler-build
+rattler-build package inspect ./*.conda
+```
+
+---
+
+# Exercises
+
+## Installing from local conda channels
+
+Publish the package to a local conda channel on your filesystem and
+then install the `rescale` Pixi package in a new Pixi workspace.
+
+## Publish to a personal conda channel
+
+Publish the conda package to a personal
+[prefix.dev conda channel](https://prefix.dev/channels).
+
+---
+
+# Compiled packaging: `collatz`
+
+Take the `collatz` package from _A minimal compiled package with
+scikit-build_ and repeat the same steps:
+
+1. `pixi init --format pyproject`
+2. Enable the preview feature: `preview = ["pixi-build"]`
+3. Add platforms with `pixi workspace platform add`
+4. Swap `[tool.pixi.pypi-dependencies]` → `[tool.pixi.dependencies]`
+5. Add `[tool.pixi.package]` and the `pixi-build-python` backend
+
+Compiled extensions need a little more configuration...
+
+---
+
+# Compilers and dependency mapping
+
+```toml
+[tool.pixi.package.build.config]
+compilers = ["cxx"]
+ignore-pypi-mapping = false  # Enable automatic PyPI-to-conda mapping
+```
+
+- Declare the **compiler types** you require — Pixi Build figures out
+  the rest
+- `ignore-pypi-mapping = false` (somewhat confusingly) **enables**
+  automatic PyPI-to-conda name mapping, so the `host` dependencies
+  (`scikit-build-core`, `pybind11`) don't need to be redefined
+
+---
+
+# Build dependencies and the Ninja gotcha
+
+The build tools come from the `build-dependencies` table:
+
+```toml
+[tool.pixi.package.build-dependencies]
+cmake = "*"
+ninja = "*"
+```
+
+`rattler-build` (through `pixi-build-python`) exports
+`CMAKE_GENERATOR='Unix Makefiles'`, overriding scikit-build-core's
+default of Ninja — restore it with explicit arguments:
+
+```toml
+[tool.scikit-build]
+# c.f. https://github.com/prefix-dev/rattler-build/issues/2487
+cmake.args = ["-GNinja"]
+```
+
+---
+
+# Just over 20 lines of TOML
+
+The complete set of additions that turn `collatz` into a conda package:
+
+<div class="columns">
+<div>
+
+```toml
+[tool.scikit-build]
+cmake.args = ["-GNinja"]
+
+[tool.pixi.dependencies]
+collatz = { path = "." }
+
+[tool.pixi.package]
+name = "collatz"
+version = "0.1.0"
+```
+
+</div>
+<div>
+
+```toml
+[tool.pixi.package.build.backend]
+name = "pixi-build-python"
+version = "0.*"
+
+[tool.pixi.package.build.config]
+compilers = ["cxx"]
+ignore-pypi-mapping = false
+
+[tool.pixi.package.build-dependencies]
+cmake = "*"
+ninja = "*"
+```
+
+</div>
+</div>
+
+---
+
+# Exercises (1/2)
+
+## Build and install the conda package
+
+Build `collatz` as a conda package and install it into your Pixi
+workspace environment.
+
+## Build a conda package archive
+
+Build `collatz` as a local conda package archive, publish it to a
+local channel, and inspect it.
+
+---
+
+# Exercises (2/2)
+
+## Install collatz as a conda package from source
+
+Add `collatz` as a source dependency to a Pixi workspace and install it
+as a conda package
+([full example](https://github.com/scikit-build/SIMPLE-Py/tree/main/examples/5_02_pixi_build/compiled)).
+
+## Install a conda package from a new channel
+
+`collatz` was published on the conda channel
+<https://prefix.dev/matthewfeickert> — create a new workspace and
+install from that channel.